Unit Testing of jBPM Process Flows

Unit testing is an important step in the software development life cycle to ensure that your product works the way it is intended to work. Back in the day, it used to be just a step that developers had to perform to evaluate their work. In today’s world, it has become an essential part of the CI/CD pipeline as it is not just used to determine quality based on functionality but also to determine code promotion eligibility based on various numbers (pass/fail ratio or code coverage percentage).

jBPM, being one of the most modern, open-source bpm products, provides rich capabilities for unit testing BPM processes. This allows jBPM processes to be treated just like any other Java-based artifact. The jBPM tool kit provides an extension of JUnit test classes that allow one to easily unit test business processes defined in BPMN2.

We will look at a sample implementation where we use out-of-the-box unit testing capabilities provided by jBPM. jBPM provides a test module (jbpm-test.jar) that includes all of the classes needed for creating jBPM unit tests. It is easy to include the jbpm-test module to your jBPM project. You just need to add the dependency to your pom.xml.

<dependency>
   <groupId>org.jbpm</groupId>
   <artifactId>jbpm-test</artifactId>
   <version>7.17.0.Final</version>
</dependency>

The jBPM test module provides the JbpmJUnitBaseTestCase class, which provides various method implementations to support BPMN2 process unit testing .

JbpmJUnitBaseTestCase class provides support in four major areas. Some of the most important ones in those areas are listed below:

JUnit Life Cycle Methods

•  setup(): This is an @Before annotated method to create EntityManagerFactory and cleans up the Singleton's sessionID

•  teardown(): This is an @After annotated method, which clears out history, closes EntityManagerFactoryand the data source, and disposes of the RuntimeEngines and RuntimeManager.

KIE Session Management Methods

• createRuntimeManager()

• disposeRuntimeManager() 

• getRuntimeEngine() 

Assertions

•  assertProcessInstanceCompleted 

•  assertProcessInstanceActive 

•  assertNodeTriggered 

•  assertProcessVarExists 

Helper Methods

•  getTestWorkItemHandler() — returns test work item handler that might be registered in addition to what is registered by default

•  setupPoolingDataSource() — sets up the data source

Below is a sample implementation using the JbpmJUnitBaseTestCase.

public class HelloWorldTest extends JbpmJUnitBaseTestCase  {

public HelloWorldTest() {
    // This helps to setup data source and session persistence
        super(true, true);
}

    @Test
    public void testHelloWorld() {
      createRuntimeManager("com/sample/HelloWorld.bpmn2");
      RuntimeEngine runtimeEngine = getRuntimeEngine();
      KieSession ksession = runtimeEngine.getKieSession();
      ProcessInstance processInstance = ksession.startProcess("com.sample.HelloWorld");
      assertProcessInstanceCompleted(processInstance.getId());
      disposeRuntimeManager();
    }
}

This approach allows us to test basic process status and its life cycle. This is with the assumption that a process is high level and doesn’t have too many implementation logic embedded in the process. Currently, there is no way to measure the code coverage and branch in BPM processes. Hopefully it will come in future versions.